Almost everyone is using Internet and web-based services as a primary means of conducting business. Services such as email, e-commerce, Voice over IP (VoIP), and web-browsing have become critical to communication within and across organizations. As reliance on network based services increase, so do consumer demands for availability, reliability, and responsiveness of the services. Typically, the customers do not care how the service is composed, to them the quality of service (QoS) is what is important. In order to provide appropriate QoS, network providers must enforce the flip-side of QoS, which is policy. Policy defines the rules that determine the specifics of how, when and where QoS is applied to various network traffic.
Quality of Service itself refers to the classification of packets for the purpose of treating certain classes or flows of packets in a particular way compared to other packets. The classification and treatment criteria are the policy terms. Ideally, QoS and policy means making the delivery service of the otherwise unpredictable best effort broadband network, predictable.
Many standards have been created and implemented, at least to some extent, to attempt to provide QoS to Internet Protocol (IP) networks such as the Internet. Examples of such standards include DiffServ, MPLS, and RSVP. All of these standards require the setting of fields within the packet headers (DiffServ) or the insertion of shims into packet headers (MPLS) so that properly enabled network equipment will be able to read the particular QoS tag and treat the packet accordingly. their traffic belongs to a user or network with higher QoS than their own. Consequently, there is a need to be able to identify the source, destination and nature of the traffic independently, without relying on the source user or network to correctly identify the traffic it is passing.
Since there are varying circumstances in which traffic owners, be they end users, applications, Internet hosts, companies, or network providers, are entitled to the services they request, there is a need for rules, for enforcement of the rules, and for deciding when the rules apply. The rules, enforcement and decision making comprise a policy system that is an essential component of a QoS enabled network.
Accordingly, what is needed is a network processing system that can enforce network policies by determining the nature of the traffic flowing through it, determining the proper treatment for each packet and flow in the traffic, and modifying and routing each packet in accordance with the treatment.